1. Field of the Invention
This invention relates to a manipulator, and particularly to a manipulator suitable for use in medical procedures, including minimally invasive surgical operations.
2. Description of the Related Art
In conventional open surgery on the interior of the human body, a surgeon must make an incision large enough to permit access to a region of interest as well as to allow a direct line of sight to the region. However, with the development of endoscopes, surgical tools which can be manipulated from outside a patient""s body, and various imaging techniques such as ultrasonic imaging, computer tomography, and magnetic resonance imaging, it has become possible to perform surgery through very small incisions or body orifices of a size through which traditional open surgery would be impossible. Such surgery is generally referred to as minimally invasive surgery.
A typical surgical device for use in minimally invasive surgery includes an elongated tube having a first end which is inserted into a patient""s body through an incision or orifice and a second end which extends to the outside of the patient""s body and which is grasped by the surgeon. The first end is equipped with a surgical tool, such as a stapler, forceps, scissors, a needle holder, or a scalpel, while the second end is equipped with a handle or other member which is grasped by the surgeon and which is mechanically connected to the tool through the center of the tube. By manipulating the handle, the surgeon can operate the tool, and he can change the position of the tool by adjusting the orientation of the tube with respect to the patient""s body.
Minimally invasive surgery, when feasible, is highly advantageous to the patient because it involves less trauma than does open surgery. It also frequently results in lower medical costs and shorter hospital stays. However, conventional minimally invasive surgical devices have a number of drawbacks. One drawback is that the surgeon can easily become fatigued by the need to manually support the minimally invasive surgical device during its use. Another drawback is that conventional minimally invasive surgical devices require the surgeon to assume an awkward position of his hands. Furthermore, conventional minimally invasive surgical devices can produce angular magnification of errors. As a result, a surgeon has considerably less dexterity and precision when performing an operation with minimally invasive surgical devices than when performing an operation by traditional techniques in which the surgeon grasps a tool directly. Therefore, minimally invasive surgery is used only for surgery which requires a low level of dexterity on the part of the surgeon.
The present invention provides a manipulator which is suitable for surgery and particularly minimally invasive surgery.
The present invention also provides a manipulator which can be used for diagnostic or therapeutic medical procedures.
The present invention further provides a manipulator which can decrease the fatigue of a surgeon during a surgical operation while increasing dexterity and precision.
The present invention also provides a manipulator having a high mechanical bandwidth.
The present invention additionally provides a manipulator having a small diameter so that it can be inserted into a small incision or body orifice of a patient.
The present invention yet further provides a method of performing various medical procedures, including surgical, diagnostic, and therapeutic procedures, with such a manipulator.
According to one form of the present invention, a manipulator includes first and second independently movable arms and a medical tool pivotably supported by both arms. The arms can be moved to manipulate the tool with one or more degrees of freedom. For example, in one preferred embodiment, the arms can manipulate the tool with five degrees of freedom.
The arms may manipulate the tool by various types of motions of the arms, such as by rotation of the arms as a whole about corresponding axes, or by translation or pivoting of parts of each arm with respect to each other to produce elongation or contraction of the arms or a change in the shape of the arms.
The manipulator may include a wrist capable of manipulating the tool with respect to the arms to provide the tool with additional degrees of freedom. In a preferred embodiment, the wrist and the tool can be detached from other portions of the manipulator to permit easy sterilization and replacement of the tool.
A manipulator according to the present invention can be operated in a variety of modes, including a master-slave mode in which its motions are controlled by a master controller, a robotic mode, or a semi-robotic mode in which some operations are robotic and other operations are controlled by a master controller.
A manipulator according to the present invention has numerous advantages over conventional minimally invasive surgical devices. For one, the surgeon does not need to support any portion of the manipulator during its operation, so the manipulator is less fatiguing for a surgeon to use, particularly during long operations. The manipulator can also support a medical device at an attitude which would be difficult to achieve by hand. In conventional minimally invasive surgery, the body wall through which an minimally invasive surgical tool is inserted typically must be substantially level and facing upward. In contrast, a manipulator according to the present invention imposes no restrictions on the orientation of the body wall through minimally invasive surgery is performed. For example, the body wall could be vertical or facing downward if the patient can be placed on a table having an opening through which the manipulator can pass to access the body wall. Thus, a patient can be positioned in a manner which is comfortable for the patient and the surgeon and advantageous with respect to patient safety and recovery.
Another significant advantage of a manipulator according to the present invention is that it can enhance the dexterity of the user. Whereas a conventional minimally invasive surgical device invariably reduces the dexterity of the surgeon compared to his dexterity when operating by hand, a manipulator according to the present invention can provide the surgeon with dexterity comparable or even superior to that achievable by the unaided hand.
A manipulator according to the present invention is particularly suitable for minimally invasive surgical operations or other medical procedures performed through small incisions in the body wall of a patient. However, a manipulator according to the present invention can be used in medical procedures other than minimally invasive surgery, such as for external surgery or traditional open surgery entailing large incisions in the body wall. It can also be used in non-medical applications. For example, it can be employed as a general purpose manipulator for use in manufacturing, repair, installation, or support of various objects.